There are people out there that use them. Most of the big companies now use CNC to at least rough out there product.
You wouldn't need a very big machine to do what you are asking. What you need to look for is the travel of the bed and the z-axis clearance. Also you would probably want a vertical mill.
If you want to buy a machine buy the BIGGEST machine that you can afford and have space for. This is stated for two primary reasons:
1)You will always be restricted to the size of a small machine.
2)You can do even really small thing on a big machine, and you have the size to do big projects and as soon as you have a machine and start using it you will always get an idea for a big project and wish you had a bigger machine.
At least that is what I get from my experience in machining.